Presently, communication systems generally include a network operator serving user devices through a dedicated access network. For example, wireless communication systems in general comprise a Radio Access Network (RAN) and a core network (CN). The RAN includes base stations and associated radio network controllers providing wireless communication links with user devices (UDs), also referred to herein as user equipment (UE). The core network receives messages from a public switched telephone network (PSTN), other mobile stations, the Internet, other core networks, and other network entities. The wireless communication system is coupled to other wireless communications systems, but each respective system is typically operated by one operator or carrier. Such systems are currently used for landlines such as cable and twisted wire pair systems, and wireless systems such as Global System for Mobile communication (GSM), other time division multiple access (TDMA) systems, and code divisions multiple access (CDMA) networks for example.
In some mobile communications systems the mobile device is required to perform a location update at certain times. For example, in GSM and UMTS systems the mobile is required to perform a location update or a routing area update whenever it is determined that the mobile has changed its location area or routing area. The change in location determination may be based on received broadcast information. Other reasons for a location update include expiration of a periodic timer for the location update, a registration message such as a first International Mobile Subscriber Identity (IMSI) attach, and a variety of other occurrences or events. In order to perform the location update the mobile reads the broadcast information, determines that the location area has changed, and requests a radio channel from the network. In GSM systems, the network allocates a Standalone Dedicated Control Channel (SDCCH) for the mobile to use to transmit the location update message. In UMTS systems, the network allocates a Radio Resource Control (RRC) connection.
In certain network configurations, the boundaries of location areas are such that there are very frequent location area changes as determined by the mobile reading of the broadcast information. For example, the location area seam may run parallel to and in the middle of a major roadway, such as a heavily traveled expressway. In such cases, during peak traffic times (such as a so-called “rush hour”), the mobile may fail to receive an SDCCH allocation due to load/resource constraints at the network. The mobile is therefore unable to receive an SDCCH allocation and consequently will subsequently fail to inform the network of its change in location area.
Location areas are used by the core network to track the mobile in idle mode. For example, the network will determine the appropriate paging area to be used when a page is to be sent to the mobile. When the mobile fails to update the network of a change in its location area, the network may send the page to the radio networks corresponding to the wrong location area such that the mobile will fail to receive the paging message, causing a missed connection with the subscriber and a loss of revenue to the operator.
In the case of wireless systems, although each system operator generally uses one type of system, e.g., either CDMA, wideband CDMA (WCDMA) or TDMA, operators may operate multiple systems in a geographic area in an effort to use legacy systems to insure full coverage. For example, an operator may have an analog system and a CDMA system, or an analog system and a TDMA system, or a TDMA system and a third-generation system. Additionally, a number of operators may cover the same geographic area, wherein each operator using its own network. Each wireless communication system operates in an assigned frequency band, also called a spectrum, as there are only a finite number of available bands. However, with the current systems the system operator links the RAN to a single core network. The RAN broadcasts a message that includes identifiers for the core network coupled to the RAN, such as a PLMN, location areas and routing areas for the core network, and the like. With such dedicated systems, the RAN can serve only a single core network.
It is desirable for communication systems to allow network operators to share resources. One example of a shared network resource is twisted wire connections and cables connected to residences and offices. This infrastructure is already installed, expensive to replace, and is available to multiple operators if the network owner desires resource sharing. Another example of a network that can be shared is the radio access network where it may be desirable to share resources by allowing multiple core networks, operated for example by different operators, to connect to users through a shared radio network controller (RNC) and its associated base stations. This allows multiple network operators to access subscribers using the same spectrum, and through the same radio access network. For example, a license holder of a particular spectrum may want to sell access via their radio access network to other network operators to offset the cost of the system, while operators who do not have a spectrum license in a geographical area may want to buy access to that spectrum from the license holder.
An additional challenge in wireless systems, such as the emerging universal mobile telephone system (UMTS), is to accommodate circuit switched and packet switched data. The routing of messages to one of many core networks is limited by the basis of the core network domain type, i.e., packet switched or circuit switched, and not by system operator, as only one system operator uses the radio network and the core network for both circuit switched and packet switched communications.
Thus, there is a need for an improved method of uniquely supporting multiple user devices.